<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
</head>
<body>

<script type="text/javascript">

// var num=90;
// num>60 ? alert("及格"):alert("不及格");

var num=80;
//判断
//赋值
num =num > 60 ? '胖':'瘦';
console.log(num);
</script>
</body>
</html>